Postal rates have been steadily increasing for the past several years and postage costs have become a greater and greater burden for mailers. To help in controlling postage costs, mailers, particularly larger mailers, have a need for a means to account for postage expended on a departmental and/or a customer basis in order to maintain closer control of postage costs and to facilitate charge back of such costs. Such mailers will typically have one or more postage meters. (Postage meters are well-known devices which imprint appropriate postal indicia and account for postage expended up to a pre-set limit.) Given the need to control postage costs through closer departmental or customer accounting and the fact that postage meters only record total postage expended, there is a need for systems to facilitate accounting for the postage expended through a postage meter.
One such system is disclosed in U.S. Pat. No. 4,319,328, For: Postage Cost Recording System, To: Eggert, Issued: Mar. 9, 1982. In the system disclosed, a postage computer sets a mechanical postage meter in accordance with information received from a postal scale and records postage for each item metered in response to a signal from a "item feed sensor". Other such systems include the Electronic Accounting System (EAS) and the Electronic Journal Printer (EJP) marketed by Pitney Bowes Inc. of Stamford, Conn.
It will be apparent to those skilled in the art that an important feature of such systems is data security. Clearly such systems will fail of their object if data may be lost or altered by power failure or transients, or through inadvertent or fraudulent operation of the system. Heretofore, such systems have relied upon the use of non-volatile memory to secure data during power failure and on the use of special supervisory access codes for functions such as editing of accounts. One example of a technique for data security is disclosed in U.S. Pat. No. 4,323,987 to Holtz et al. The system taught in this patent includes a back-up battery power supply which is connected to a volatile memory if an impending power failure is detected. The system further includes a timer which measures the duration of the power failure and initiates a transfer of the memory contents to an external device such as a printer for later recovery.
While systems using such techniques have been generally successful, some problems have remained. Despite the use of non-volatile memory power failures or transients which occur at critical times such as during print out of account records or editing of account records, may still result in the loss of account data. Also, it has been found that operators have in practice often obtained the supervisory access code and erroneously edited account records.
Through their experience with such previous systems, Applicants and their co workers have learned that the sensitivity of such systems to power failures or transients when outputting or editing account records arises out of the nature of mailroom operations. When users create accounts, they will, in general, wish to assign identifying account numbers in accordance with their own pre-existing systems. As a result, the account numbers of account records stored in non-volatile memory will, in general, be random with respect to the sequence in which the account records are stored. When these records are printed out, however, the users want the print out to be in account number order for ease of use. As a result in previous systems, it has generally been necessary to sort the data base of the account records before the records are output. As the Applicants have realized, the problem here is that a power failure or transient which occurs at the point where a record has been partially rewritten, may result in the loss of the data in that account. Similarly, when an account is edited, a power failure or transient which occurs when the edited account is only partially updated, will effectively result in the loss of the data in that account since it will in general be difficult or impossible to identify which items in the account have been updated and which have not been updated.
Accordingly, it is an object of the subject invention to provide a system for accounting for postage expended through a postage meter.
More particularly, it is an object of the subject invention to provide such a system which has improved data security in the event of a power failure or transient when account records are being output or edited.